1. It is a conflict management tool used widely across a diverse set of contentious cases, running the gamut from divorce settlement talks to labor management negotiations to peace efforts between warring states.
2. Regardless of the type of conflict to which it is applied, the distinguishing feature of this concept is the introduction of an outside or third party into the negotiation process between the disputing sides with, at least partially, the aim of producing a settlement between the two sides.
   What concept possesses these features?